在外ないし最近まで在外だった日本人経済学者のツイートをここ数日で幾つか目にした際に、以前ブクマ/ツイートしたクルーグマンのエントリ「誰に耳を傾けるべきか(Who To Listen To)」の追記部分を否応無く思い出したので、以下にそれを紹介してみる。

PS: One side note: One thing that’s striking in Portes’s discussion — and something I very much agree with — is the irrelevance of formal credentials. As we’ve debated how to deal with the worst slump since the 1930s, a distressing number of economists have taken to arguing on the basis that they have fancy degrees and you don’t — or in some cases that well, you may have a fancy degree too, and even a prize or two, but in the wrong sub-field, so there.

But all this counts for very little, especially when macroeconomics itself — or at any rate the kind of macroeconomics that has dominated the journals these past couple of decades — is very much on trial. And note Portes’s praise for Martin Wolf, which I heartily second; Wolf doesn’t even have a PhD. And that matters not at all; what he has is a keen sense of observation, a level head, and an open mind, all attributes lacking in far too many of my colleagues.

ここで「ポルテスの議論」となっているのは、Jonathan Portes英経済社会研究所*1プリンシパルリサーチフェローの2012/7/30付けの表題のブログエントリ(原題は「Which (macro)-economists are worth listening to?」)のことで、クルーグマンはエントリ本文でその内容に賛意を表し、人(クルーグマン自身を含む)ではなくモデルに信を置くべし、と書いている。

This post relates to the ongoing blog debate on "the state of macroeconomics", which I contributed to here, and which has drawn in a whole host of economics bloggers who know far more about modern macroeconomic theory than I do. However, here I want to address a related, more mundane question, but one which is perhaps more relevant to most non-economists' concerns. That is, when economists argue about the correct stance of policy, who should we (policymakers, commentators, and the general public) listen to?
This question was prompted by a recent exchange I had with Ed Vaizey and Simon Hughes on the BBC's Daily Politics: I pointed out that not only was the government's decision in 2010 to cut the deficit too quickly doing considerable economic damage, but that this was both predictable and predicted by economists such as Paul Krugman and Martin Wolf. Their response was essentially "how were we to know which economists to listen to? Others were saying the opposite".
This is a fair question. My answer to it is that policymakers and the public should listen to economists who fulfill two critera: first, they have made empirically testable predictions (conditional or unconditional - see Krugman here) that have proved, by and large, to be broadly consistent with the data; and second, they base those predictions on an analytic framework (not necessarily a formal model) that is persuasive. In other words, getting it right alone is not enough; it should be possible to show your workings - to explain why you got it right. Otherwise, your predictions may be interesting, but they tell you little about how to formulate policy.
My shortlist (apologies in advance to those I've omitted) of economists commenting on macroeconomic policy who I think qualify is something like the following:

  • Krugman, Delong and Wren-Lewis on fiscal policy when interest rates are at the zero lower bound;
  • Adam Posen on monetary policy when interest rates are at the zero lower bound;
  • Paul de Grauwe on sovereign and eurozone debt;
  • Martin Wolf on private sector savings and public sector deficits (the financial balance approach);
  • Richard Koo on the implications of a "balance sheet recession"

This in turn generates an obvious list of economists or those commenting on economic issues who got it completely wrong, usually because they were using analytic frameworks that were incoherent or lacked empirical evidence. I won't name individuals here, so I leave that to readers, but a short list of influential bodies that should have known better includes those responsible for writing editorials at the Financial Times, macroeconomic forecasters at the OECD, the European Department at the IMF (up until recently - their recent stuff on both UK and eurozone has been pretty good) , the senior leadership at the Bank of England and the Treasury, and probably worst of all senior economic policymakers at the ECB and European Commission. Oh, and the credit ratings agencies, but that goes without saying.
この疑問が浮かんだのは、BBCの「Daily Politics」でエド・バイゼイとサイモン・ヒューズと意見を交わしたことがきっかけになっている。私は、2010年に債務を急過ぎるほど急速に削減するという政府の決定は著しい経済的損害をもたらしたが、そのことは予測可能であったと同時に、ポール・クルーグマンマーティン・ウルフといった経済学者は予測していた、と指摘した。彼らの反応は基本的に「どの経済学者に耳を傾けるべきかどうやったら我々に分かる? 他の経済学者は反対のことを言っていたのだ」というものだった。



I don't think there's any doubt that if policymakers, both in the UK and elsewhere (especially in the eurozone) had, during the intervening period, listened to these people rather than their own economic advisers, the state of the UK and world economies would be significantly better than it is now.

*1:NIESR=National Institute of Economic and Social Research(cf. National Institute of Economic and Social Research - Wikipedia)。なお、名前にNationalと付いており、国立経済社会研究所と訳されることが多いが、About us | National Institute of Economic and Social Researchには独立系と記されている。